Search found 96 matches

by Joshua Chung 2D
Sun Feb 28, 2021 10:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Shorthand notation
Replies: 3
Views: 18

Re: Shorthand notation

It goes (from left to right) anode, ion compound, ion, double line, ion, ion compound, anode.
by Joshua Chung 2D
Sun Feb 28, 2021 10:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anodes and Cathodes
Replies: 22
Views: 42

Re: Anodes and Cathodes

Oxidation takes place at the anode, so the substance will have lower reduction potential.
Reduction takes place at the cathode, so the substance will have higher reduction potential.
by Joshua Chung 2D
Sun Feb 28, 2021 10:34 pm
Forum: Balancing Redox Reactions
Topic: Finding Reagents From Provided Table
Replies: 9
Views: 23

Re: Finding Reagents From Provided Table

Yes, I personally found it helpful to just ctrl+f the particular element in question.
by Joshua Chung 2D
Sun Feb 28, 2021 10:33 pm
Forum: Balancing Redox Reactions
Topic: Sapling Week 7/8 #7
Replies: 6
Views: 32

Re: Sapling Week 7/8 #7

I've tried switching up the order of the elements on either side and get different, unhelpful error messages each time, so if someone did this question right, let me know. Hello, this is what I was able to get hope it helps. Thanks so much, this worked! But can anyone explain why this is correct an...
by Joshua Chung 2D
Sun Feb 28, 2021 10:28 pm
Forum: Balancing Redox Reactions
Topic: states of matter
Replies: 38
Views: 71

Re: states of matter

Yes, for some questions (I don't particularly remember how many exactly), the state of matter is required.
by Joshua Chung 2D
Sun Feb 21, 2021 10:40 pm
Forum: Calculating Work of Expansion
Topic: adiabatic processes
Replies: 18
Views: 32

Re: adiabatic processes

No. Adiabatic processes have no heat transfer, so q=0 and delta U=w. Since w is the energy transferred through work rather than heat, w is not affected by whether or not a process is adiabatic.
by Joshua Chung 2D
Sun Feb 21, 2021 10:38 pm
Forum: Van't Hoff Equation
Topic: Equation Sheet
Replies: 7
Views: 34

Re: Equation Sheet

You can use either, they just have the negative sign in different places.
by Joshua Chung 2D
Sun Feb 21, 2021 10:36 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G and G naught
Replies: 37
Views: 97

Re: Delta G and G naught

Delta G naught is simply Delta G under standard conditions (273 K / 0˚C, 1 atm).
by Joshua Chung 2D
Sun Feb 21, 2021 10:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Forward vs. Reverse
Replies: 15
Views: 30

Re: Forward vs. Reverse

A reaction moves forward from left to right (as given to you). Since the reactants are on the left and the products are on the right, a forward reaction is R —> P. Thus, the reverse of the same reaction moves from right to left, or P —> R.
by Joshua Chung 2D
Sun Feb 21, 2021 10:31 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Meaning of K
Replies: 47
Views: 93

Re: Meaning of K

In this context, K is always the equilibrium constant.
by Joshua Chung 2D
Sun Feb 14, 2021 9:56 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Change in entropy
Replies: 4
Views: 20

Re: Change in entropy

You can use the equation delta S = deltaH/T, where delta S is taken from the surroundings and delta H is taken from the system.
by Joshua Chung 2D
Sun Feb 14, 2021 9:54 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: qrev vs q
Replies: 19
Views: 56

Re: qrev vs q

There isn't really a notable difference, just that qrev is used to specify that the heat value is taken from a reversible system.
by Joshua Chung 2D
Sun Feb 14, 2021 9:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversible vs Irreversible Work
Replies: 5
Views: 24

Re: Reversible vs Irreversible Work

Reversible work is much slower, more efficient, and takes an infinite number of infinitely small steps. On the contrary, irreversible work is done rapidly and/or in large jumps one direction or another.
W = -Pex delta V is used for irreversible work, and W = -nRTln(V2/V1) is used for reversible work.
by Joshua Chung 2D
Sun Feb 14, 2021 9:50 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: molar heat capacity
Replies: 9
Views: 42

Re: molar heat capacity

Molar heat capacity is defined as the amount of energy needed to raise 1 mol of a certain substance by 1 degree Celsius. Enthalpy, on the other hand, is applied to chemical reactions/phase changes. It is defined as the amount of energy absorbed or released as a process takes place. Molar heat capaci...
by Joshua Chung 2D
Sun Feb 14, 2021 9:46 pm
Forum: Calculating Work of Expansion
Topic: U, q, w
Replies: 11
Views: 53

Re: U, q, w

delta U = q + w. You can substitute 0 for q if the system does no work, such as if it is isothermal. Thus, you can also substitute 0 for w if no work is being done, such as if there is no external pressure or no change in volume.
by Joshua Chung 2D
Sun Feb 07, 2021 9:39 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity of Calorimeter
Replies: 7
Views: 32

Re: Heat Capacity of Calorimeter

I was just wondering, how we are supposed to know if something is a an atom, linear molecule, or nonlinear molecule, like those pertaining to question 20 on the sapling assignment, that were used to fid the heat capacity? For that specific problem, the molecule name was given to you (ex: H2). You c...
by Joshua Chung 2D
Sun Feb 07, 2021 9:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q and internal energy
Replies: 8
Views: 24

Re: q and internal energy

The standard equation for internal energy is deltaU = q + w. Since w = -PdeltaV, w will be 0 when deltaV is 0. In other words, deltaU=q when the volume is constant.
by Joshua Chung 2D
Sun Feb 07, 2021 9:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling #10 Week 3/4
Replies: 6
Views: 34

Re: Sapling #10 Week 3/4

Since the ice is already at 0 degrees celsius, it doesn't need to change temperature to undergo a phase change. Thus, we only use the enthalpy of fusion to account for the shift from solid to liquid, and then use the heat capacity of water afterwards to account for changes in temperature after the p...
by Joshua Chung 2D
Sun Feb 07, 2021 9:27 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Can heat capacities be negative?
Replies: 52
Views: 159

Re: Can heat capacities be negative?

No, because by definition the heat capacity is the amount of heat required to raise the temperature of a substance by 1 degree. Since you cannot increase temperature by taking away heat, heat capacity will always be positive.
by Joshua Chung 2D
Sun Feb 07, 2021 9:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters
Replies: 10
Views: 27

Re: Calorimeters

Calorimeters are simply used to calculate the transfer of heat in a reaction, whether it moves in or out of the system.
by Joshua Chung 2D
Sun Jan 31, 2021 9:44 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpies of Formation using Hess's Law
Replies: 18
Views: 82

Re: Standard Enthalpies of Formation using Hess's Law

You can flip and rearrange the reactions used, just make sure that you keep track of which direction that they end up in so that you use the correct sign for the enthalpy when calculating.
by Joshua Chung 2D
Sun Jan 31, 2021 9:41 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 58
Views: 182

Re: Hess's Law

Hess's Law states that enthalpy is a state function, meaning that it doesn't take into consideration how the enthalpy arrived at its current value. Thus, enthalpies are additive, making it very straightforward for us to problem solve with them.
by Joshua Chung 2D
Sun Jan 31, 2021 9:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sapling Week 3/4 #6
Replies: 14
Views: 48

Re: Sapling Week 3/4 #6

Since this reaction is a textbook example of a combustion reaction, we can immediately single that out as the most likely answer. If we look at the other possibilities, the bond enthalpies don't line up (as described above). Thus, the enthalpy is equal to the combustion of CH4.
by Joshua Chung 2D
Sun Jan 31, 2021 9:33 pm
Forum: Phase Changes & Related Calculations
Topic: standard form
Replies: 14
Views: 124

Re: standard form

Pretty sure we don't have to memorize every standard state besides the diatomic molecules as mentioned above (H2, N2, F2, etc.)
by Joshua Chung 2D
Sun Jan 31, 2021 9:32 pm
Forum: Phase Changes & Related Calculations
Topic: Define Phase Change
Replies: 76
Views: 224

Re: Define Phase Change

A phase change is whenever a substance changes its state of matter (solid, liquid, or gas).
by Joshua Chung 2D
Sun Jan 24, 2021 9:11 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Week 2 Sapling 5
Replies: 5
Views: 50

Re: Week 2 Sapling 5

I was running into the same issue as you; turns out that I simply wasn't using the right value for B[initial]. Keep in mind that B[initial]=[B] + [x], and you should get an appropriate percentage.
by Joshua Chung 2D
Sun Jan 24, 2021 9:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O as a Gas
Replies: 69
Views: 454

Re: H2O as a Gas

If it is a gas, then we include it. If it is in liquid form (as is in most chemical equations dealt with so far), then we exclude it.
by Joshua Chung 2D
Sun Jan 24, 2021 9:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Justin Sarquiz Step-Up Question
Replies: 9
Views: 58

Re: Justin Sarquiz Step-Up Question

You can start solving this problem by writing out the chemical equation with the appropriate conjugate acids and bases. In this case, the K+ ions are spectator ions, so you can exclude them from your solving process. Then, set up an ICE box to solve.
by Joshua Chung 2D
Sun Jan 24, 2021 9:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximately x
Replies: 18
Views: 72

Re: Approximately x

According to Dr. Lavelle, we can use this approximation when the K-value is smaller than 10^-4.
by Joshua Chung 2D
Sun Jan 24, 2021 9:02 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 86
Views: 1437

Re: Kelvin or Celsius?

Default to Kelvin here.
by Joshua Chung 2D
Sun Jan 17, 2021 3:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ice Box Method
Replies: 14
Views: 81

Re: Ice Box Method

Since we can choose to use + or - x for each of the compounds in a reaction, we simply have to determine which direction the reaction will shift with the given change. If it will shift to the right, we use -x for the reactants and +x for the products, and vice versa.
by Joshua Chung 2D
Sun Jan 17, 2021 3:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #5
Replies: 6
Views: 48

Re: Sapling Week 1 #5

For this question, I found it helpful to write out the expressions for each chemical equation's K value (using the brackets and such). Then, you can see that you can get the desired K value by multiplying the K of the reciprocal of equation 1 by equation 3.
by Joshua Chung 2D
Sun Jan 17, 2021 3:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximations
Replies: 4
Views: 29

Re: Approximations

Since any value to 10^-4 is extremely small, it is deemed "close enough" to zero to treat it as zero in your calculations.
by Joshua Chung 2D
Sun Jan 17, 2021 3:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Chart with Gas Pressures
Replies: 8
Views: 56

Re: ICE Chart with Gas Pressures

Yep; they are completely interchangeable in this coursel; just remember to keep the units of measurement consistent throughout the problem.
by Joshua Chung 2D
Sun Jan 17, 2021 3:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: shifts left or right
Replies: 23
Views: 90

Re: shifts left or right

If a reaction is shifting to the left, then it will begin to produce more reactants relative to products. If it is shifting to the right, then it will produce more products relative to reactants.
by Joshua Chung 2D
Mon Jan 11, 2021 12:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 9
Views: 70

Re: Le Chatelier's Principle

It outlines how reactions adjust to changes in concentration, pressure, and temperature.
by Joshua Chung 2D
Mon Jan 11, 2021 12:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increasing Pressure by Adding an Inert Gas
Replies: 6
Views: 43

Re: Increasing Pressure by Adding an Inert Gas

Since inert gases don't react with anything, all the concentrations will remain proportional.
by Joshua Chung 2D
Sun Jan 10, 2021 11:59 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing pressure by adding gas
Replies: 13
Views: 78

Re: Changing pressure by adding gas

Yes, as adding an inert gas will not change the reaction. Only by changing individual concentrations will the reaction be affected.
by Joshua Chung 2D
Sun Jan 10, 2021 11:58 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 7
Views: 57

Re: Le Chatelier's Principle

The principle specifies how reactions will naturally balance themselves out from changes, meeting the same k value.
by Joshua Chung 2D
Sun Jan 10, 2021 11:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: adding heat
Replies: 15
Views: 102

Re: adding heat

Since endothermic reactions require heat to occur, increasing temperature will aid in meeting the activation energy.
by Joshua Chung 2D
Sun Dec 13, 2020 1:18 pm
Forum: Bond Lengths & Energies
Topic: hydrogen bonding vs ion-dipole
Replies: 5
Views: 56

Re: hydrogen bonding vs ion-dipole

Ion-dipole forces are stronger than hydrogen bonds, as hydrogen bonds are simply a strong type of dipole-dipole forces. Since ion-dipole forces are always stronger than dipole-dipole, ion-dipole forces are stronger than hydrogen bonds.
by Joshua Chung 2D
Sun Dec 13, 2020 1:16 pm
Forum: Bond Lengths & Energies
Topic: Higher Melting Point
Replies: 27
Views: 261

Re: Higher Melting Point

Since Iodine is a larger molecule than Fluorine, the bond is stronger due to it being easier to distort its electrons. Thus, the compound with iodine is harder to break, resulting in a higher melting point.
by Joshua Chung 2D
Sun Dec 13, 2020 1:15 pm
Forum: Lewis Structures
Topic: Octet rule
Replies: 12
Views: 119

Re: Octet rule

Think of it as the third row p-block elements can have expanded octets, and B, Be, Li, He, and H can have less than an octet.
by Joshua Chung 2D
Sun Dec 13, 2020 1:13 pm
Forum: Lewis Structures
Topic: Lewis Acids and Bases
Replies: 3
Views: 37

Re: Lewis Acids and Bases

Writing out the lewis structure would help here. In this compound, boron has only three bonds and no lone pairs, so can easily accept electrons from a lewis acid.
by Joshua Chung 2D
Sun Dec 13, 2020 1:11 pm
Forum: Ionic & Covalent Bonds
Topic: Polar Bonds
Replies: 19
Views: 139

Re: Polar Bonds

You look at the geometry and the differences in electronegativity. If there are clear differences that do not cancel out, then the bond is polar.
by Joshua Chung 2D
Sun Dec 13, 2020 1:09 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 33
Views: 240

Re: Covalent Character

The less difference in electronegativity (look at position on periodic table), the more covalent it is.
by Joshua Chung 2D
Sun Dec 06, 2020 10:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question about Shape
Replies: 5
Views: 41

Re: Question about Shape

Yep, both are angular. Keep in mind that the angles are slightly less than those for a typical trigonal planar and tetrahedral structure, as lone pairs "push" other regions of electron density more than bonds. Thus, the observed bonds are more squished together.
by Joshua Chung 2D
Sun Dec 06, 2020 10:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 4
Views: 50

Re: Bond angle

The central atom is bound to two atoms and has two lone pairs, thus holding 4 regions of electron density. This forms a tetrahedral-esque structure, which has a 109.5 degree bond angle.
by Joshua Chung 2D
Sun Dec 06, 2020 10:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Structure Names
Replies: 5
Views: 76

Re: Structure Names

Octahedral structures are formed when 6 bonds orient regularly around a central atom, forming a structure with 8 faces (thus lending the name "octahedron"). I think of bipyramidal structures as two pyramids sharing a base, forming a shape similar to the green thing from Sims.
by Joshua Chung 2D
Sun Dec 06, 2020 10:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 7
Views: 40

Re: Polarity

Yes; once you determine the shape of the molecule, you can see if the dipole moments cancel each other out geometrically. If so, then the molecule is nonpolar.
by Joshua Chung 2D
Sun Dec 06, 2020 10:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar v nonpolar molecules
Replies: 30
Views: 179

Re: polar v nonpolar molecules

First, you gotta determine the differences in electronegativity between the individual atoms. If none exist or if they cancel each other out, then the molecule is nonpolar. If there is a noticeable direction of electronegativity difference, then the molecule is polar.
by Joshua Chung 2D
Sun Nov 29, 2020 10:15 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 21
Views: 192

Re: Sigma and Pi Bonds

I'm not completely sure if double bonds are commonly referred to as pi bonds, but they include one sigma and one pi bond. Thus, it is distinct from a normal pi bond (ie single bond).
by Joshua Chung 2D
Sun Nov 29, 2020 10:13 pm
Forum: Ionic & Covalent Bonds
Topic: More Covalent
Replies: 8
Views: 85

Re: More Covalent

You can either look at the number of bonds formed (more bonds=more covalent) or the bond length (shorter=more covalent).
by Joshua Chung 2D
Sun Nov 29, 2020 10:12 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic radius
Replies: 18
Views: 149

Re: Ionic radius

More electrons = larger radius and vice versa, as adding additional electrons will increase their repulsion from the nuclei.
by Joshua Chung 2D
Sun Nov 29, 2020 10:10 pm
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 386

Re: Homework due date

Sunday night at 12 am.
by Joshua Chung 2D
Sun Nov 29, 2020 10:10 pm
Forum: Sigma & Pi Bonds
Topic: Sapling Q #16
Replies: 14
Views: 140

Re: Sapling Q #16

Delocalized simply means that there exist resonance structures for the compound, so the pi bond(s) can exist in multiple different positions.
by Joshua Chung 2D
Sun Nov 22, 2020 9:06 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Angle
Replies: 8
Views: 72

Re: Bond Angle

There is no need to memorize specific bond angles for different compounds. However, bond angles can be calculated and/or estimated by playing around with the fact that a circle has an angle of 360 degrees. For example, you can deduce that a trigonal planar molecule has bond angles of about 360/3=120...
by Joshua Chung 2D
Sun Nov 22, 2020 9:03 pm
Forum: Ionic & Covalent Bonds
Topic: Molecule size and ionic character
Replies: 13
Views: 143

Re: Molecule size and ionic character

Although molecule size is often correlated with its ionic character, a better way to determine ionic character is by looking at the difference in electronegativity between the bonded elements. The greater the difference, the stronger ionic character the molecule exhibits.
by Joshua Chung 2D
Sun Nov 22, 2020 9:01 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 14
Views: 93

Re: Covalent Character

You simply look at the difference in electronegativity between the bonded elements. For example, a molecule with carbon and hydrogen is extremely covalent because they are very similar in electronegativity.
by Joshua Chung 2D
Sun Nov 22, 2020 8:59 pm
Forum: Ionic & Covalent Bonds
Topic: Polar/ Nonpolar
Replies: 23
Views: 179

Re: Polar/ Nonpolar

Shape can be used to determine if a molecule is polar or nonpolar, but you must consider whether or not it has existing dipole moments. If dipole moments are not present or if they cancel each other out (with respect to shape), then it is nonpolar. If they exist and do not cancel out, then it is pol...
by Joshua Chung 2D
Sun Nov 22, 2020 8:57 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Lewis acids and bases
Replies: 22
Views: 135

Re: Lewis acids and bases

Generally, you can determine which molecules accept (acids) or donate (bases) by looking at their respective Lewis Structures. Lone pair electrons usually indicate that the molecule is a base.
by Joshua Chung 2D
Sun Nov 22, 2020 8:55 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Best Formal Charge Equations
Replies: 24
Views: 144

Re: Best Formal Charge Equations

Personally, I take the number of valence electrons (V) and subtract from it the number of bonds (s/2) combined with the number of non-bonding electrons (L).
by Joshua Chung 2D
Sun Nov 15, 2020 8:26 pm
Forum: Lewis Structures
Topic: Sapling Question #4
Replies: 5
Views: 62

Re: Sapling Question #4

In general, comparing the given bond lengths to the values on the table provided should give a strong indication of ample or overwhelming characteristics. In other words, on an exam, the difference between the two classifications should be extremely clear, and will allow you to simply make your best...
by Joshua Chung 2D
Sun Nov 15, 2020 8:24 pm
Forum: Lewis Structures
Topic: Sapling Weeks 5/6 HW #18
Replies: 7
Views: 63

Re: Sapling Weeks 5/6 HW #18

In the case of dispersion forces, larger molecules have stronger attraction due to the distance between the nuclei and the outer electrons. Since the outer electrons in large atoms are more loosely held compared to smaller atoms, they are more easily affected by external charges.
by Joshua Chung 2D
Sun Nov 15, 2020 8:21 pm
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bonding
Replies: 13
Views: 89

Re: Hydrogen Bonding

When an H atom is bonded to a N, O, or F atom, it causes a notable electronegativity difference due to the strong electronegativity of N, O, and F. Thus, the present partial charges allow for the formation of a hydrogen bond.
by Joshua Chung 2D
Sun Nov 15, 2020 8:20 pm
Forum: Ionic & Covalent Bonds
Topic: Difference on how atomic size affects covalent and dipole interactions
Replies: 9
Views: 46

Re: Difference on how atomic size affects covalent and dipole interactions

Yep, that's exactly right. Just to clarify for dispersion forces, larger atomic radii cause weaker attraction between the outer electrons and the nuclei, thus allowing for easier polarization.
by Joshua Chung 2D
Sun Nov 15, 2020 8:17 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance Structures
Replies: 5
Views: 44

Re: Resonance Structures

A way to think about hybrid resonance is by taking the "average" of the known resonance structures for the molecule. All the bonds that differ between the structures are "averaged out" to form the hybrid structure.
by Joshua Chung 2D
Sun Nov 08, 2020 7:31 pm
Forum: Quantum Numbers and The H-Atom
Topic: ml and number of possible electrons
Replies: 6
Views: 53

Re: ml and number of possible electrons

You're spot on! Since ms is the variable that specifies the spin of the electrons, there are two possible electron states for each ml value.
by Joshua Chung 2D
Sun Nov 08, 2020 7:30 pm
Forum: Quantum Numbers and The H-Atom
Topic: Spin state
Replies: 25
Views: 211

Re: Spin state

As others have already said, it refers to which direction that the electron is spinning on the axis. In short, it's just another level of specificity when it comes to describing electrons/electron behavior.
by Joshua Chung 2D
Sun Nov 08, 2020 7:29 pm
Forum: Quantum Numbers and The H-Atom
Topic: Are there subshells past f?
Replies: 28
Views: 177

Re: Are there subshells past f?

Yes, but we don't have to worry about them for this class.
by Joshua Chung 2D
Sun Nov 08, 2020 7:28 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 4s before 3d Orbital
Replies: 11
Views: 89

Re: 4s before 3d Orbital

This is considered an "exception" to the general rule of increasing energy through orbitals, as the 4s is lower energy than 3d. Thus, it is filled first, specifically with d-block elements. However, 3d is still written before 4s when notating electron configuration.
by Joshua Chung 2D
Sun Nov 08, 2020 7:25 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: S and P electrons
Replies: 14
Views: 115

Re: S and P electrons

Since p-electrons are further away from the nucleus of the atom, they have higher energy, as is required to keep them on the atom.
by Joshua Chung 2D
Sun Nov 08, 2020 7:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital vs Subshell
Replies: 7
Views: 93

Re: Orbital vs Subshell

N specifies which shell is being isolated, l specifies which subshell of that shell, and ml specifies which orbital of that subshell. Thus m, l, and ml are increasing in terms of specificity.
by Joshua Chung 2D
Sun Nov 01, 2020 7:02 pm
Forum: Trends in The Periodic Table
Topic: Hydrogen on the periodic table
Replies: 3
Views: 34

Re: Hydrogen on the periodic table

Generally, Hydrogen is placed in group 1 on the Periodic Table. However, it shares some properties with both group 1 and group 17, so some arguments can be made on its classification. But overall, it's just a unique element.
by Joshua Chung 2D
Sun Nov 01, 2020 7:00 pm
Forum: Trends in The Periodic Table
Topic: ionic radius
Replies: 14
Views: 71

Re: ionic radius

As anions have extra electrons and cations have less electrons than the "normal" state of the element, anions are larger and cations are smaller.
by Joshua Chung 2D
Sun Nov 01, 2020 6:58 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Simplifying Electron Configurations
Replies: 9
Views: 66

Re: Simplifying Electron Configurations

As other people seem to have already answered the first part of your question quite thoroughly, I thought I'd add that by convention, noble gases are the only elements used as shorthand reference elements (due to their convenience both in location on the table and for having a complete outer shell a...
by Joshua Chung 2D
Sun Nov 01, 2020 6:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration For Calcium
Replies: 7
Views: 75

Re: Electron Configuration For Calcium

K and Ca are simply exceptions to the rules applied to the previous elements, as 4s is lower energy than 3d. Thus, for these two elements, 4s is written before 3d in order to keep with the convention that configurations are written with ascending energy.
by Joshua Chung 2D
Sun Nov 01, 2020 6:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 4s and 3d
Replies: 14
Views: 135

Re: 4s and 3d

The third is written before the fourth simply because it notates a lower n-value (shell). Since these are written in ascending order by convention, 3d will always come before 4s.
by Joshua Chung 2D
Sun Nov 01, 2020 6:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 4s and 3d
Replies: 14
Views: 135

Re: 4s and 3d

The third is written before the fourth simply because it notates a lower n-value (shell). Since these are written in ascending order by convention, 3d will always come before 4s.
by Joshua Chung 2D
Sun Oct 25, 2020 10:17 pm
Forum: Photoelectric Effect
Topic: Mass of atoms
Replies: 18
Views: 105

Re: Mass of atoms

Other people have pretty much covered it, but just make sure that your SI units align in your equations, and when in doubt double check the conversions.
by Joshua Chung 2D
Sun Oct 25, 2020 10:15 pm
Forum: Properties of Electrons
Topic: Lyman and Balmer series
Replies: 6
Views: 64

Re: Lyman and Balmer series

For most problems, you just have to know that the Balmer series covers jumps starting or ending at n=2, and the Lyman series with n=1. Also, the Balmer covers the visible regions of the EM spectrum, and the Lyman covers UV regions. I'm pretty sure you don't need to know the specific frequency limits...
by Joshua Chung 2D
Sun Oct 25, 2020 10:05 pm
Forum: Properties of Electrons
Topic: rydberg equation
Replies: 8
Views: 64

Re: rydberg equation

As other people have said, n1 is the lower energy level and n2 is the higher one (in emission equations). Another way to remember it is to make sure that the value of (1/n1^2)-(1/n2^2) is always positive.
by Joshua Chung 2D
Sun Oct 25, 2020 10:02 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 25
Views: 161

Re: Speed of light

Though 3.0 will probably be fine in most questions, you can round to math the sig figs of the given values just to be safe.
by Joshua Chung 2D
Sun Oct 25, 2020 9:04 pm
Forum: Properties of Light
Topic: Amplitude
Replies: 9
Views: 66

Re: Amplitude

Yes, amplitude is specifically a feature of wave models. However, increasing the amplitude of a light source will not increase its energy - only its intensity. The only way (that's been mentioned in class so far) to change energy is to change frequency.
by Joshua Chung 2D
Sun Oct 18, 2020 10:33 am
Forum: Photoelectric Effect
Topic: Excess energy
Replies: 20
Views: 135

Re: Excess energy

This equation is used to find the kinetic energy of the electron, which is essentially the leftover energy after the threshold energy is used up to eject the electron in the first place.
by Joshua Chung 2D
Sun Oct 18, 2020 10:31 am
Forum: Photoelectric Effect
Topic: Question about Short Wavelengths vs. Long Wavelengths
Replies: 6
Views: 80

Re: Question about Short Wavelengths vs. Long Wavelengths

Essentially, the wavelength determines whether or not the light will be able to eject electrons, as higher wavelength = higher energy of the photons. Since intensity refers only to the number of photons of light emitted, increasing intensity while not changing wavelength will not affect whether or n...
by Joshua Chung 2D
Sun Oct 18, 2020 10:27 am
Forum: Photoelectric Effect
Topic: Frequency vs. Intensity
Replies: 16
Views: 133

Re: Frequency vs. Intensity

The light must meet a certain frequency in order to eject electrons from the material. Since the intensity only refers to the number of photons and not their energy level, increasing the intensity but not the frequency will not affect whether or not electrons are ejected.
by Joshua Chung 2D
Sun Oct 18, 2020 10:24 am
Forum: Properties of Electrons
Topic: Work function/Threshold Energy
Replies: 19
Views: 95

Re: Work function/Threshold Energy

In the context of the Photoelectric effect, both are interchangeable. They both refer to the minimum amount of energy to remove one electron from the specified material.
by Joshua Chung 2D
Sun Oct 18, 2020 10:22 am
Forum: Administrative Questions and Class Announcements
Topic: Where can I buy a webcam for a reasonable price?
Replies: 60
Views: 1168

Re: Where can I buy a webcam for a reasonable price?

There's a ton on Amazon, just have to make sure you get one that's compatible with your computer.
by Joshua Chung 2D
Fri Oct 09, 2020 8:05 pm
Forum: Empirical & Molecular Formulas
Topic: Calculation Errors for Empirical Formulas
Replies: 10
Views: 67

Re: Calculation Errors for Empirical Formulas

As long as you use enough decimal points throughout your calculations, the numbers should come out to be very clear/close to the correct ratios.
by Joshua Chung 2D
Fri Oct 09, 2020 8:04 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical and Molecular Formula
Replies: 17
Views: 132

Re: Empirical and Molecular Formula

Jaden Kwon 3I wrote:Is there ever a situation where the empirical formula would be used over the molecular formula?

It depends on the question, but in most cases (unless specifically stated) the molecular formula takes priority, especially since it links directly to molecular masses, etc.
by Joshua Chung 2D
Fri Oct 09, 2020 8:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's #
Replies: 31
Views: 387

Re: Avogadro's #

Avogadro's number is applicable to situations where you need to find or use a number of specific things, such as molecules or atoms (usually a very large quantity of small things).
by Joshua Chung 2D
Fri Oct 09, 2020 2:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7317

Re: Accessing the E-textbook [ENDORSED]

Is there a free trial access for the textbook? I bought the book but I don't think it'll get here in time for me to be able to do the assignments. Any help would be amazing, thank you There's an option to do a free trial for a few days; it should show up on the page that you're prompted to submit t...
by Joshua Chung 2D
Fri Oct 09, 2020 2:46 pm
Forum: SI Units, Unit Conversions
Topic: Angstroms
Replies: 7
Views: 66

Re: Angstroms

Using a capital A most likely works; the actual symbol might also be accessible through special characters.
by Joshua Chung 2D
Fri Oct 09, 2020 2:46 pm
Forum: SI Units, Unit Conversions
Topic: Angstroms
Replies: 7
Views: 66

Re: Angstroms

Using a capital A most likely works; the actual symbol might also be accessible through special characters.

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